Abstract

OSINOWO, Olawale Olakunle; ADABANIJA, Moruffdeen A.  and  ADEWOYE, Oluwatoyin Adebayo. Structural Interpretation and Depth Estimation from Aeromagnetic Data of Abigi-Ijebu-Waterside area of Eastern Dahomey Basin, Southwestern Nigeria. Geofís. Intl [online]. 2019, vol.58, n.4, pp.259-277.  Epub Oct 07, 2020. ISSN 2954-436X.

High Resolution Aeromagnetic (HRAM) data of Abigi-Ijebu waterside in eastern part of Dahomey Basin southwestern Nigeria were analyzed and interpreted in terms of structures, basement geometry and sedimentary thickness to evaluate the petroleum potential of this sector of the Dahomey Basin as well as provide relevant information that could support the hydrocarbon exploration campaign of the neglected eastern arm of the basin, which has lately proved prolific with the discovery of Aje and Ogo oil fields in the offshore part of the basin. The HRAM data were filtered to remove cultural and background noise, upwardly continued and reduced to pole at low latitude to simplify and focus the peaks of magnetic anomalies positively symmetrical over corresponding geologic sources. Derivative filtering delineated and enhance preferentially aligned magnetic signatures that reflect the structural framework of the study area. Radial spectral analysis and Euler deconvolution depth weighting techniques were employed to determine depth to magnetic sources which generated the basement topography and thus the thickness of sedimentary rocks overlying the crystalline rocks.

The derivatives and tilt derivative filters enhanced and delineated several linear regional structures, some of which are over 15 km in length and trend mainly along NE -SW direction. Spectral analysis and 3D Euler deconvolution depth weighting solutions indicate that the depth to the top of magnetic anomalies ranges from around 100 m above the Minna reference datum to over 2.0 km below the datum. The basement topography as revealed by the Euler solution plots indicate gradual and gently depressing crustal basement rocks which may be aided by regional faults that gradually stepped down or depressed the crustal rocks southward for increase sediment accommodation. This therefore suggests increase in the hydrocarbon prospect potential southward of the study area, especially in the offshore and deeper into the Atlantic Ocean.

Keywords : tilt angle; derivative filters; euler deconvolution; basement topography; hydrocarbon potential; dahomey basin.

        · abstract in Spanish     · text in English     · English ( pdf )